This invention relates to a machining control method for performing mutual control between coordinate systems in a machine tool having plural coordinate systems. This invention relates to a machining control apparatus suitable for application to a complex machine tool having two workpiece spindles which are free to move relative to each other in the Z axis direction and having two tool rests which are free to move in the X axis direction. Furthermore, this invention relates to a machining control apparatus suitable for application to a complex machine tool having plural spindles.
Recently, a machine tool has been provided with many coordinate systems to be controlled because of the addition of a handling robot and the like, and the increase of control axes. The cases are increasing in which the coordinate data of one coordinate system such as a parameter affects the other coordinate system.
Heretofore, in such a case, since each coordinate system is independent without mutual relation to the other systems, it is necessary to recalculate the coordinate data so as to fit those coordinate systems for each coordinate system and to input its data in the form of overlapping data to each coordinate system, even if the coordinate data relates to the sam dimension.
However, the more the control coordinate systems, the more complicated the input operation becomes and there is a tendency to make mistakes in the prior art machines.
On the other hand, in recent years, a proposal by which the same machining is performed on each workpiece spindle, so that the machining is executed with high efficiency, has been made which uses a complex machine tool having two workpiece spindles mutually facing and free to move in the Z axis direction relative to each other, and having two tool rests provided free to move in the X axis direction.
However, when the simultaneous machining is performed, when mounting workpieces on two workpiece spindles of such a machine tool, there is some risk of interference between workpieces installed on those workpiece spindles or between a workpiece and a tool. Therefore, the development of a control apparatus capable of preventing such interference efficiently is desirable.
Furthermore, heretofore a programmer had created a machining program for every spindle separately when creating a machining program for the machining tool having this kind of plural spindles.
In general, it is necessary that the machining time of each spindle be equalized and to control a spindle so as not to generate idle time in order that machining efficiency can be kept at its maximum in such a machine tool. Accordingly, when a programmer creates a machining program, the necessity is to determine the combination of machining which is performed at each spindle in order to equalize the machining time of each spindle in a capable range.
However, such an operation requires great knowledge and skill for a programmer. Moreover, many hours are required to create such a machining program which is inconvenient.
The first purpose of this invention is to provide a machining control apparatus and machining control method for a machine tool capable of utilizing the coordinate data of one coordinate system for all the other coordinate sYstem as it is.
Furthermore, the second purpose of this invention is to provide a machining control apparatus and a machining control method capable of preventing interference between workpieces or between a workpiece and a tool without degrading machining efficiency in every way when machining is performed by means of two spindles.
The third purpose of this invention is to provide a machining control apparatus and a machining control method capable of allocating the combination of machining to each spindle without the action of a programmer (operator) in order that the combination of machining operation performed at each spindle can be optimal.